Merge "Support experimental building with OpenJDK 21" into main am: 8f7ee30d21 am: 26539fd5e8 am: a334a87934

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2853425

Change-Id: Iace8a28440c7ca1d374465b761abeddaa9b16e8b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

java/config/config.go

@@ -133,7 +133,12 @@ func init() {
 		if override := ctx.Config().Getenv("OVERRIDE_JLINK_VERSION_NUMBER"); override != "" {
 			return override
 		}
-		return "17"
+		switch ctx.Config().Getenv("EXPERIMENTAL_USE_OPENJDK21_TOOLCHAIN") {
+		case "true":
+			return "21"
+		default:
+			return "17"
+		}
 	})
 
 	pctx.SourcePathVariable("JavaToolchain", "${JavaHome}/bin")